Cleaning machines of the type wherein a washing liquid is fed from a receptacle to a surface to be washed and, then, by means of suction, is returned to the original receptacle for further use, preferably after being filtered are known. Often these units include a tank-like receptacle that houses a pump for dispensing the cleaning liquid, a suction fan for returning the liquid, and a filtering means, while also providing the storage facility for the cleaning liquid. The tank-like receptacle is designed to sit on the floor and flexible liquid discharge and liquid return hoses connect the tank-like receptacle with a cleaning head used to apply and retrieve the cleaning liquid from the surface being cleaned. In some cases, to dispense with the pump, the liquid is provided directly from a water faucet, but then the dirty liquid is collected in the tank-like receptacle from which, in some instances, it is returned to a sink or other static drain.
While devices of the aforementioned type are portable, they are anything but compact and lightweight, particularly when their cleaning fluid tank is full. Furthermore, the presence in such apparatus of a separate tank that must rest on the floor not only makes use of the apparatus cumbersome, but is restrictive with respect to the places that such a unit can be effectively utilized. For example, long flights of steps having no landing upon which the tank can rest can render the apparatus unusable. Furthermore, because of the cumbersome nature of such units, it is often impractical to utilize the unit for spot cleaning purposes, such as cleaning up a small spill, as opposed to general room cleaning.
As a result, it is desirable to have a cleaning apparatus wherein all of the operative components are mounted upon a common element so that the unit is unencumbered by a separate floor-supported tank. In view of this, floor cleaning devices have been configured to be similar to an upright vacuum cleaner or so-called electric broom, and have all of the operative components for spraying a cleaning fluid onto a floor surface, such as a carpet, and for using suction to collect the dirty cleaning liquid, as well as a means for storing the fluid that is applied and collected mounted upon a common element. However, such devices are often not constructed to enable recycling of the cleaning fluid, and therefore the cleaning capacity of the apparatus is severely limited by the amount of fluid that can be carried. Furthermore, the versatility of such "common element" type cleaning apparatus is severely restricted to floor-type uses because these units are too large and heavy to be used in a manner that is unsupported by contact with the floor surface to be cleaned and because the units are not designed for operation in orientations that would be necessary for cleaning vertical surfaces.
To overcome these disadvantages, relatively small, light-weight, easily portable and versatile cleaning units have been developed which recycle the cleaning fluid employed so that the cleaning capacity of the unit is not limited to the surface area that can be cleaned with a single application of a limited quantity of cleaning fluid carried by the unit. Instead, the fluid which is applied to a surface and then vacuumed back into the unit is recycled and used again. My previous U.S. Pat. Nos. 4,788,738 and 4,930,178 show improved cleaners of this type.
A common feature of all prior cleaners which first apply and then vacuum cleaning fluid from a surface is that the fluid removed from the surface is limited to that which can be entrained in a vacuum stream collated by a suction or vacuum generator mounted on the device. If the surface is formed by a carpet or other fluid absorbent material, a significant amount of the fluid will be absorbed and may remain after the vacuum operation is complete. This leaves an area which remains wet, often for several hours, until normal air drying occurs. Also, in cases where a liquid spill is to be vacuumed from a hard surface, such as a hardwood floor, removal dependent solely upon a vacuum stream is often insufficient and a slippery, wet floor surface remains.
A further problem encountered with previous units is the effective separation of fluid from air when the fluid-air mixture is extracted from a surface to be cleaned. Baffles within a cleaner plenum chamber have been used to accomplish this separation, but baffles and other obstructions in the plenum chamber tend to create turbulence which causes fluid to remain entrained in an air stream.